Start by taking the connections off the chassis batteries and cleaning the contact surfaces shiny clean. For safety, remove the negative (black wire) first then the positive (red). Put the connections back in reverse order. Your symptoms are classic for corroded battery terminals. If this doesn't work, come back with more information, such as what chassis and engine you have.

Clicking generally means low voltage to the relay, so either a bad wire connection or weak batteries, or a combination of those two. A poor [chassis] ground is a common cause, either at the chassis battery or at the relay.

I have a 1999 Bounder 36S and I am having the same problems on vacation in New Mexico now. I also agree that the battery terminals can be problem because that's what got mine going today after cleaning them. Over a period of time the corrosion creeps up into the insulated part of the cables and that can weaken the leads. I've heard of several remedies for corrosion but can't recall them maybe someone can respond to how to help keep corrosion down. Most of my electrical has come from loose fuse holder clips. I also have found loose grounds as mentioned.

You can use baking soda to remove corrosion from the battery terminals, but what I do instead is buy a spray can of battery terminal cleaner and another of terminal protector from your local Auto Zone(or whatever). Spray the cleaner on(it turns from yellow to red when it contacts battery acid), scrub the terminals with a wire brush, rinse with clear water, wait for it to dry and then spray the terminals with the protectant.I usually do this every couple of months when I check the battery water levels.